• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.189-192
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• 2004

This paper focuses on a TCP window-based flow control mechanism with Explicit Congestion Notification (ECN). We investigate the fundamental problem of achieving a fair window control for TCP, which cooperates with ECN. This is done by using feedback congestion pricing as a means of estimating the state of bottleneck router. The problem is solved by achieving network optimal performance, which maximize the total user utilities. We then look at the simulation of such scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권6호
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• pp.1101-1112
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• 2011

The Multiuser Eigenmode Transmission (MET) has generated significant interests in literature due to its optimal performance in linear precoding systems. The MET can simultaneously transmit several spatial multiplexing eigenmodes to multiple users which significantly enhance the system performance. The maximum number of users that can be served simultaneously is limited due to the constraints on the number antennas, and thus an appropriate user selection is critical to the MET system. Various algorithms have been developed in previous works such as the enumerative search algorithm. However, the high complexities of these algorithms impede their applications in practice. In this paper, motivated by the necessity of an efficient and effective user selection algorithm, a low complexity recursive user selection algorithm is proposed for the MET system. In addition, the fairness of the MET system is improved by using the combination of the proposed user selection algorithm and the adaptive Proportional Fair Scheduling (PFS) algorithm. Extensive simulations are implemented to verify the efficiency and effectiveness of the proposed algorithm.

• Journal of Medicine and Life Science
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• 제19권1호
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• pp.14-19
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• 2022

We investigated the safety and efficacy of pemetrexed monotherapy in patients with lung adenocarcinoma and various renal conditions, including chronic kidney disease. We also analyzed whether baseline renal function affected progression-free survival (PFS). We retrospectively analyzed 71 patients who received maintenance-and second-line pemetrexed monotherapy. Patients were divided into two groups according to estimated glomerular filtration rate (eGFR): fair eGFR (>60 mL/min/1.73 m²) and lower eGFR (59 mL/min/1.73 m² or less). The safety and efficacy were evaluated for each group. Median ages were 73.2 years in the lower eGFR group (n=28) and 64.5 years in the fair eGFR group (n=43). Patients with a lower eGFR achieved a median PFS of 4.7 months, while the median PFS for patients with a fair eGFR was 2.7 months. The difference between the two groups was not statistically significant (P=0.075). Both groups showed treatment-related low-grade hematological and non-hematological adverse events. Pemetrexed monotherapy is safe and effective in patients with lung adenocarcinoma with a lower eGFR.

• 보건교육건강증진학회지
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• 제32권2호
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• pp.75-84
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• 2015

Objectives: This study examines that the compatibilities between the health promotion programs in community health center and the leading health indicators in National Health Plan. Methods: We analyzed health promotion programs associated with three health indicators; smoking(smoking rate in male), alcohol use(alcohol use rate in adults), obesity(obesity rate) in twenty five community health centers in Seoul. First, we classified three groups(excellent, fair and poor groups) using average scores of Seoul, that of Korea and National Health Plan2010 goals in three health indicators. Afterwards, we examined the compatibility between contents of health promotion programs regarding leading health indicators and the specific program activities. Results: The compatibility levels between health indicators and contents of health promotion programs was 80 % for smoking among fair and poor groups while fair and poor for smoking reported 60% and 70%, respectively. For obesity, excellent group reported 80% and fair group had 91%. Conclusion: In conclusion, although all districts were able to access available data for health indicators and health statistics every year, it seems that they did not only utilize these data enough in conjunction with health promotion programs but also did not integrate specific activities according to National Health Plan systematically.

• 제어로봇시스템학회논문지
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• 제6권8호
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• pp.638-651
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• 2000

When the bandwidth resources in a packet-switched network are shared among sessions by MAX-MIN flow control each session is required to transmit its data into the network subject to the MAX-MIN fair rate which is solely determined by network loadings. This passive behavior of sessions if fact can cause seri-ous QoS(Quality of Service) degradation particularly for real-time multimedia sessions such as video since the rate allocated by the network can mismatch with what is demanded by each session for its QoS. In order to alleviate this problem we extend the concept of MAX-MIN fair bandwidth allocations as follows: Individual bandwidth demands are guaranteed if the network can accommodate them and only the residual network band-width is shared in the MAX-MIN fair sense. On the other hand if sum of the individual bandwidth demands exceeds the network capacity the shortage of the bandwidth is shared by all the sessions by reducing each bandwidth guarantee by the MAX-MIN fair division of the shortage. we present a novel flow control algorithm to achieve this extended MAX-MIN fairness and show that this algorithm can be implemented by the existing ATM ABR service protocol with minor changes. We not only analyze the steady state asymptotic stability and convergence rate of the algorithm by appealing to control theories but also verify its practical performance through simulations in a variety of network scenarios.

• 한국통신학회논문지
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• 제39C권12호
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• pp.1280-1288
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• 2014

본 논문에서는 선박 내 IT 서비스에 대한 요구에 부응하기 위해 적응적이고 합리적인 무선 주파수를 활용하는 인지무선 기술 중 최초 표준인 ECMA-392 네트워크를 사용한다. 먼저, ECMA-392 기반 네트워크에 대해서 알아보고, 디바이스에게 채널 할당을 위한 고려사항 및 문제점을 살펴본다. 그리고, ECMA-392 MAC 프로토콜에서 디바이스 그룹들이 요청하는 채널을 효율적으로 보장하기 위한 공평한 채널 자원 할당 방법을 제안한다. 새로운 디바이스 그룹과 기존의 디바이스 그룹들에게 채널 할당 파라미터를 고려하여 공평하게 채널들을 재할당할 수 있는 방법이다. 시뮬레이션 결과는 제안된 방식이 기존의 방식에 비해 데이터 수율을 향상시키고 있음을 나타낸다.

• Physical Therapy Rehabilitation Science
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• 제11권3호
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• pp.311-320
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• 2022

Objective: To investigate the reliability and validity of static balance measurements using an acceleration sensor and a gyroscope sensor in smart phone inertial sensors. Design: Equivalent control group pretest-posttest. Methods: Subjects were forty five healthy adults aged twenty to fifty-years-old who had no disease that could affect the experiment. After pre-test, all participants wore a waist band with smart phone, and conducted six static balance measurements on the force plate twice for 35 seconds each. To investigate the test-retest reliability of both smart phone inertial sensors, we compared the intra-correlation coefficient (ICC 3, 1) between primary and secondary measurements with the calculated root mean scale-total data. To determine the validity of the two sensors, it was measured simultaneously with force plate, and the comparision was done by Pearson's correlation. Results: The test-retest reliability showed excellent correlation for acceleration sensor, and it also showed excellent to good correlation for gyroscope sensor(p<0.05). The concurrent validity of smartphone inertial sensors showed a mostly poor to fair correlation for tandem-stance and one-leg-stance (p<0.05) and unacceptable correlation for the other postures (p>0.05). The gyroscope sensor showed a fair correlation for most of the RMS-Total data, and the other data also showed poor to fair correlation (p<0.05). Conclusions: The result indicates that both acceleration sensor and gyroscope sensor has good reliability, and that compared to force plate, acceleration sensor has unacceptable or poor correlation, and gyroscope sensor has mostly fair correlation.

• 유통과학연구
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• 제10권11호
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• pp.55-60
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• 2012

Purpose - This study aims to suggest policy directions for small retail markets in Korea by statistical analysis, which would help small retailers who are facing various difficulties. Research design, data, methodology - This study diagnoses the problems faced by small retail industries in Korea based on government statistics. In addition, this study identifies three areas for successful collaboration between the SSMs and traditional markets-information distribution, products, and fair trade. Results - This study makes three recommendations-information distribution, products, and fair trade. This includes activation of the existing mutual collaboration efforts, channels, CSR report writing and publicity, ethical management cooperation seminars, contract systems of no return, establishment of staff outsourcing standards, and support for suppliers' organizations. Conclusions - Our suggestions for a collaborative system (based on the three suggestions) show that collaboration rather than confrontation between large and small markets can lead to a sales increase of 2,258.2 billion Won, which is equivalent to the sales loss in 11 traditional markets in one year in Busan.

• 재무관리연구
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• 제26권3호
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• pp.103-138
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• 2009

본 논문은 2003년 1월부터 2004년 9월까지 표본기간동안 한국유가증권시장의 전자공시시스템인 KIND를 통해 접속매매시간 동안 장중에 발표되는 비실적 관련 공정공시 표본 자료를 일중 사건연구로 분석하여 실시간 정보에 대한 효율성을 검증하였다. 장중 발표되는 공정공시 정보에 대해 주가는 평균적으로 2분 이내에 유의적으로 강하게 반응하는 것으로 나타났다. 또한 공시 발표 시점 2분 이후부터 10분까지는 추가적인 양의 주가 반응이 있었으나, 이후 시간에는 소폭 반전하는 형태를 보였다. 공정공시 종류별로 볼 때 기타사항 공시를 제외한 사업계획 공시나 경영사항 공시에 대해서는 공시 발표 2분 이후부터 20분까지의 시간에는 추가적으로 유의적인 주가의 반응은 발견되지 않았다. 한편 공시 정보에 대한 주가 반응의 크기는 소기업 표본의 공시일수록 강한 것으로 나타났으며, 규모가 큰 종목의 표본에서는 2분 이후에 정보가 지연되는 현상이 발견되었으나 5분 이후로 지속되지는 않은 것으로 나타났다. 이 같은 결과는 기업 특유 정보 내용(firm-specific information)의 공시에 대해서는 대기업보다는 소기업에서 반응하는 속도가 상대적으로 빠르다는 것을 의미한다. 공시 정보를 이용하여 거래비용을 제외하고도 초과수익률을 획득할 수 있는지를 분석한 결과에서는 공시 시점 이후 매입하는 전략은 모두 음의 수익률을 보였다. 반면에 공시 발표 시점 이전과 공시 시점에서 매입하는 전략은 평균적으로 2분이 경과한 다음부터 양의 수익을 시현하는 것으로 분석되었다. 공시 발표 시점에서 소형주를 매입할 경우 2분 이후부터 양의 초과 수익이 발생하지만, 대형주는 10분이 지나도 양의 초과 수익을 획득할 수 없었다. 이상의 결과를 종합하면 투명한 전자 공시 체제를 운영하는 한국유가증권시장은 실시간적으로 준강형 정보 효율성이 높은 시장이라 할 수 있다.

• 한국도서관정보학회지
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• 제33권4호
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• pp.19-35
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• 2002

최근 유럽연합에서는 공공도서관의 무료대출에 대해 저작자에게 보상하는 공공대출권 보상제도의 실시를 회원국들에게 권장하고 있다. 본고는 EU 및 선진국 일부에서 제도화하고 있는 공공대출권(Public Lending Right)제도의 운영실태 및 문제점 살펴보았다. 또한 기왕에 공공대출권 제도를 운영하고 있는 각국의 현황분석을 통해, 도서관 공정사용의 전통을 고수하면서 저작자의 대여권을 보상하는 합리적인 보상시스템을 모색해 보았다.